Histology of muscle Flashcards
(23 cards)
What are the two myofilaments?
Thick filament
Thin filament
What is the primary component of thick filaments?
Myosin II
What is the primary component of thin filaments?
Actin
What is a sarcolemma?
Muscle cell membrane
What is sarcoplasm?
Cytoplasm of a muscle cell
What are sarcosomes?
Muscle cell mitochondria
What is sarcoplasmic reticulum?
Muscle cell ER
What are the three CTs found in skeletal muscle?
Epimysium
Perimysium
Endomysium
What is the role epimysium?
Separates gross muscle into fascicles
What is the role of perimysium?
Surrounds each fascicle of muscle
What is the role of endomysium?
Envelopes each individual muscle fiber within a fascicle
What is a syncytium and how does it form?
Multinucleated muscle fiber
Formed from fusion of myoblasts during development
What is the function of satellite cells?
Skeletal muscle regeneration
What is a t-tubule?
Invagination of plasma membrane between terminal cisternae at A-I junctions
What is a terminal cisternae and its function?
Channels around sarcomere composed by SR
Reservoirs of Ca++
What is a triad in muscle cells?
T-tubule and two adjacent terminal cisternae
What are the three types of skeletal muscle fibers?
Type I - slow oxidative
Type IIa - fast oxidative glycolytic
Type IIb - fast glycolytic
What is the basic structure of cardiac muscle cells?
Short, cylindrical
Central, single nucleus
How are cardiac muscle cells attached?
Intercalated discs
How do organelles in cardiac muscle cells differ from skeletal muscle?
Large numbers of mitochondria
Smaller terminal cisternae
Diads at Z-line
What is an intercalated disc?
Highly specialized cell-cell adhesion junctions
Fascia adherens
Maculae adherentes (desmosomes)
Gap junctions
What is the basic structure of smooth muscle?
Bundles or sheets of small, elongated fusiform cells with tapered ends
How does smooth muscle differ?
No T-system
No Z-lines
No sarcomeres
No myofibrils
Abundant gap junctions
